The present invention relates to a mechanical clutch provided in a motor or the like as a drive source for a vehicle door opening/closing device to perform coupling and uncoupling between a drive shaft and a driven shaft, a motor equipped with the clutch and a vehicle door opening/closing device equipped with the motor having the clutch.
In recent years, some vehicles equipped with a slide door that opens and closes a gate provided on a side of a vehicle body have been provided with a vehicle door opening/closing device for automatically opening and closing the slide door by drive force from a motor. This vehicle door opening/closing device also needs to be able to manually open and close the slide door. For example, a vehicle door opening/closing device described in Japanese Laid-Open Patent Publication No. 2002-327576 includes, in the motor as the drive source, an electromagnetic clutch that can open and close the door automatically and manually. When being turned on, the electromagnetic clutch couples the motor to the door to enable automatic opening/closing of the door, and when being turned off, the electromagnetic clutch cancels coupling between the door and the motor to enable manual opening/closing of the door.
However, the use of the electromagnetic clutch leads to complicated wiring for power supply within the motor. For this reason, for example, as described in Japanese Laid-Open Patent Publication No. 2008-133951, it is desired to replace the electromagnetic clutch with a mechanical clutch.
Such a mechanical clutch includes a driving coupling portion that can rotate integrally with a drive shaft of a motor main unit, an intermediate plate held via a spring at a predetermined relative rotational position relative to the driving coupling portion, and a driven cylindrical portion that can rotate integrally with a driven shaft coupled to the door. A roller member is arranged between the driving coupling portion and the intermediate plate, and the driven cylindrical portion in the radial direction of the clutch. During stopping of the motor main unit, the roller member is arranged at a radial inward position, that is, a non-pinching position where the roller member is not engaged with the intermediate plate and the driven cylindrical portion in the rotational direction, so that the drive shaft is uncoupled from the driven shaft. For this reason, even when the driven cylindrical portion rotates, the rotation is not transmitted to the intermediate plate not to rotate the drive shaft. Thus, the door can be easily opened/closed by hand. On the other hand, during driving of the motor main unit, as the intermediate plate rotates with rotation of the driving coupling portion, the roller member revolves. The roller member is moved radially outward by the centrifugal force generated during revolution and is arranged at a pinching position where the roller member is pinched by the intermediate plate and the driven cylindrical portion. At this time, since the intermediate plate is engaged with the driven cylindrical portion in the rotational direction via the roller member, rotation of the intermediate plate allows the driven cylindrical portion to be rotated. As a result, the driven shaft rotates and the slide door coupled to the driven shaft is automatically opened/closed.
However, in the clutch described in Japanese Laid-Open Patent No. 2008-133951, when the centrifugal force occurring at the roller member during driving of the motor main unit is too strong, the roller member moving radially outward may strike against the driven cylindrical portion, be returned to the radially inner side by the striking to the driven cylindrical portion and then, strike against the driving coupling portion and the intermediate plate. Until the driving coupling portion is coupled to the driven cylindrical portion via the roller member, that is, until the clutch is turned on, the striking may be repeated multiple times. Disadvantageously, the repeated striking between the driven cylindrical portion and the roller member, and the repeated striking between the driving coupling portion and the intermediate plate, and the roller member cause noise.